code: def Int64ByteSize(field_number, int64):
      # Have to convert to uint before calling UInt64ByteSize().
      return UInt64ByteSize(field_number, 0xFFFFFFFFFFFFFFFF & int64)
  
imports: import struct
  from google.protobuf import descriptor
  from google.protobuf import message
label_desc: Use image node_id 7 for calling a global function with example usage: Int64ByteSize(field_number, int64) and returns: UInt64ByteSize